Nitride semiconductors are used in various semiconductor devices such as semiconductor light emitting devices and HEMT (high electron mobility transistor) devices. However, the characteristics of such nitride semiconductor devices are restricted by high density threading dislocations due to lattice mismatch with the GaN crystal.
For instance, semiconductor light emitting devices based on nitride semiconductors are expected as a phosphor-exciting light source for e.g. white LED, but have low efficiency.
Various proposals have been made to increase the efficiency of LED and other semiconductor light emitting devices based on nitride semiconductors.